Mathilda gloriosa Boettger, 1907

Harzhauser, Mathias & Landau, Bernard, 2023, The Architectonicidae and Mathildidae (Gastropoda, Heterobranchia) of the Miocene Paratethys Sea-victims of the Miocene Climatic Transition, Zootaxa 5370 (1), pp. 1-74 : 49

Mathilda gloriosa Boettger, 1907

Figs 25A 1 –A 2

* Mathilda (Fimbriatella) gloriosa n. sp. —Boettger 1907: 169.

Mathilda (Fimbriatella) gloriosa Boettger — Cossmann 1912: 12.

Mathilda (Fimbriatella) gloriosa Boettger —Zilch 1934: 217, pl. 7, fig. 13.

Type material. Holotype: SMF 372691 (XII 2493a), SL: 10.9 mm, MD: 3.9 mm, Senckenberg Museum, Frankfurt/ Main, Germany, Coşteiu de Sus ( Romania), illustrated in Zilch (1934: pl. 7, fig. 13), Figs 25A 1 –A 2 .

Revised description. Medium-sized, very slender turritelliform shell; apical angle 20°. Protoconch multispiral, of about 2.5 smooth whorls, heterostrophic, nucleus fully exposed, tilted at angle of about 110°. Teleoconch of eight angulated whorls with deeply incised, canaliculate suture. First teleoconch whorl with three primary spiral cords: S1 weakest; S2 coinciding with periphery; S3 slightly weaker. Secondary spiral cord intercalated between S1 and S2 soon after protoconch/teleoconch junction, forming pair of tubercular cords of equal strength with S1 on steep sutural ramp. Abapically, S2 forming sharp keel; S3 placed just above abapical suture, forming second, weaker keel. About 50 prominent but narrow, slightly opisthocyrt axial lamellae forming cancellate pattern, with very small tubercles developed at intersections. Further fine tertiary thread intercalated between secondary and S2 on penultimate whorl. Base rapidly contracting, weakly convex, delimited by weak double peribasal cord, with five further weak wider spaced cords over base. Aperture small, ovoid, anteriorly slightly angulated. Columella weakly concave. Columellar callus forming thin rim. No parietal callus. Outer lip not preserved.

Discussion. This species is characterized by its slender shape and the mid-whorl angulation. It is reminiscent of Mathilda brocchii Semper, 1865 but differ in the narrower apical angle in M. gloriosa .; its S3 is stronger on the last whorl and lower placed and the double peribasal cord is weaker. Mathilda filogranata (Sacco, 1895) , from the Late Miocene of Italy, is broader, has a coarser sculpture and a steeper sutural ramp (see Montanaro Gallitelli & Tacoli 1951: pl. 2, fig. 3; Ferrero Mortara et al. 1984: pl. 41, fig. 8). The Pliocene Mathilda filogranata sensu Tabanelli et al. (2021) differs in its broader whorls with markedly angulated periphery and the regularly cancellate sculpture (see Tabanelli et al. 2021: figs 5–6).

Paleoenvironment. Unknown; probably middle to outer neritic.

Distribution. Only known from the Langhian equivalent of the Badenian in the Central Paratethys Sea.

Central Paratethys Sea. Middle Miocene (Badenian): Făget Basin: Coşteiu de Sus ( Romania) ( Boettger 1902).

Figures

FIGURE 1. Descriptive terms used in descriptions of Architectonicidae (modified from Bieler 1993).

FIGURE 2. Whorl cross-sections of Architectonicidae genera. All modified after Bieler (1993) except for Simplexollata, Basisulcata and Ammotectonica. Solatisonax? refers to Solatisonax? kostejana (Boettger, 1907), Bold genera are represented in the Paratethys Sea. SSC: subsutural cord, MC: mid cord(s), UPC: upper peripheral cord, LPC: lower peripheral cord, IPC: infraperipheral cord; UC: umbilical crenae; PUC: proxumbilical cord.

FIGURE 25 A1–A2. Mathilda gloriosa Boettger, 1907, holotype, SMF 372691, Coşteiu de Sus (Romania). B1–B2. Mathilda margaritula Semper, 1865, paralectotype, NHMW 1868/0001/0549a, Lăpugiu de Sus (Romania). C1–C2. Mathilda margaritula Semper, 1865, paralectotype, NHMW 1876/0011/0098, Lăpugiu des Sus (Romania). D. Mathilda margaritula Semper, 1865, paralectotype, NHMW 1868/0001/0549b, Lăpugiu de Sus (Romania). E. Mathilda margaritula Semper, 1865, lecto- type, NHMW 1868/0001/0549, Lăpugiu de Sus (Romania). F1–F2. Mathilda margaritula Semper, 1865, paralectotype, NHMW 1868/0001/0549c, Lăpugiu de Sus (Romania). G. Mathilda margaritula Semper, 1865, paralectotype, NHMW 1868/0001/0549d, Lăpugiu de Sus (Romania). H1–H2. Mathilda margaritula Semper, 1865, NHMW 1858/0047/0039a, Sedlec (Czech Republic). I1–I2. Mathilda margaritula Semper, 1865, NHMW 1866/0001/0912, Niederleis (Austria). J. Mathilda margaritula Semper, 1865, NHMW 1858/0047/0039b, Sedlec (Czech Republic). K. Mathilda margaritula Semper, 1865, NHMW 1858/0047/0039c, Sedlec (Czech Republic).